Studies on the mechanism of action of the benzodiazepines indicate that benzodiazepines alter neuronal inhibition in the central nervous system through a GABA receptor/benzodiazepine/ionophore complex. The ability to covalently label this site with a radioactive benzodiazepine has resulted in labeling of the active site. The binding of benzodiazepine agonists and antagonists (anti-diazepam) compounds has been studied and the antagonist binding site has been differentiated from the agonist binding site.